Code Engine: Required module for blinking LED via GPIO will not compile on Windows

[marusshi]

Describe the bug
The onoff module is being used to allow Code Engine to indicate a busy status via blinking LED. There is a problem requiring the onoff module on Windows because it assumes a Linux interface to access the GPIOs.

This isn't a major issue when we consider that ThingsJS is supposed to run on IoT devices but may be a problem for developers who have Windows computers.

To Reproduce
Run the things-js command on a Windows machine

Screenshots

Desktop:
Windows 10